A rich dish of mashed potatoes flavored with dried wild mushrooms. I use black trumpets here, but you could use your favorite. Chanterelles are very good.
Course: Side Dish
Keyword: Black Trumpet Mushrooms, Potatoes
1ozdried black trumpets mushrooms
1small shallot2 oz
1large clove garlicgrated or minced
1teaspoonsaltplus more to taste
Fresh slices chives or green onionsto garnish
Cover the black trumpets with the water and rehydrate for 15 minutes. P
eel the potatoes, then half and cut into 1 inch pieces. Bring the potatoes to a simmer using a pot of cold water, then turn the heat to low and cook until very tender, then drain very well and pass through a food mill into a mixing bowl while still hot. Cover the potato bowl with cling film and put in a warm place until needed.
Meanwhile, agitate the mushrooms in the water to remove grit, then lift the mushrooms out of the water. Strain the liquid slowly, discarding the last tablespoon or two since any grit will be concentrated there. Reserve the mushrooms and liquid separately.
Sweat the shallots, (grate the garlic into the pan now), in 2 tablespoons of the butter until translucent, then add the mushrooms and sweat for a few minutes more. Add the black trumpet liquid and reduce until the pan is nearly dry, then add the cream and salt, bring to a simmer, then turn down the heat and reduce for 5 minutes more on medium-low.
Pour the trumpet cream into a highspeed blender like a vitamix, or a food processor in a pinch, and puree until very smooth, using the accelerator attachment to the blender if necessary to get the blades moving, dropping in the remaining butter, emulsifying to a smooth paste. Pour the mushroom cream into the still hot riced potatoes, combine, double check the seasoning for salt and adjust until it tastes good to you.
Plating as pictured
To get the pattern on the potatoes as pictured in this post, which is how the potatoes are served at Robuchon (or at least how I was taught) take a knife with a length equal to the radius of the dish you will serve the potatoes in, put the potatoes in the dish, and smooth out the top with the blade of the knife. It takes some practice, and will frustrate most people, but you can always smooth out the top and start over if the pattern isn’t to your liking. Clean the rim of the dish with a damp towel after you're pleased with the patter.